What Has Research on Disease Burden Found Concerning the Relative

What has research on disease burden found concerning the relative impact of medical illnesses and mental disorders?

A) Medical illnesses and mental disorders are associated with equal levels of disease burden.
B) Although quite prevalent,mental disorders account for insignificant levels of disease burden.
C) Mental disorders are responsible for more disease burden than all of the medical illnesses combined.
D) Although mental disorders account for a small number of deaths,they are a significant cause of disease burden.